Diagnostic instrument with a display screen



FIG. 1 is a left front perspective view of a diagnostic instrument with a display screen showing our new design;

FIG. 2 is a right rear perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a left side view thereof; and,

FIG. 7 is a top plan view thereof.

The bottom view is plain and unornamented and is not part of the claimed design. The broken lines depict environmental structure and elements depicted in broken lines are not part of the claimed design. 

CLAIM The ornamental design for a diagnostic instrument with a display screen, as shown and described. 